Sunday, February 22, 2009

Q: Jim,Just got a new Giant racing bicycle (love it) and have been out on a maiden voyage. The frameset and many of the components are made of carbon and I am concerned about getting the torques right as I make adjustments and repairs. Do you recommend a bike-specific torque wrench (Park has one in the $40 range), or can I just go pick one up at Sears and get the same thing?

Thanks,Chris

A: Good question, Chris. Yes, I definitely recommend a torque wrench for caring for carbon bicycles and carbon components. These bikes and parts have a different feel than steel and aluminum ones and the only way to get the tightness right is by reading the instructions or looking on the components to find the recommended torque (often written on the parts), and using a torque wrench to get the bolts just tight enough.

Also, in my experience with these super bikes, things tend to loosen more and need regular checking. Anytime you're installing a new part or making adjustments, getting the torque right will ensure you never break or damage anything, which can save you a lot of money when you consider how expensive most carbon bikes and parts are.

I have 2 Park torque wrenches, like them and recommend them. The ones I have are bar-type wrenches that have an indicator needle that points at a little scale on the tool as you torque the bolt (photo). Park also shows a new click-type tool on their site that they say will be available in April. Click-type wrenches are set to the torque you require and when you're tightening the bolt, the wrench makes a click you can hear and feel when the bolt is tightened right so you can't overtighten it.

While you can get torque wrenches from places like Sears and The Home Depot and Harbor Freight, etc., I recommend bike-specific ones because most general torque wrenches are made for car work so they often provide a ton of leverage with long handles. That's not ideal for bike use where you often have to reach into small places and where you don't ever want to overtighten or break things with too much power. So, I would look for one that's not too big and that measures in inch pounds and Newton meters since bike parts are usually marked that way. The Park models do this and work fine.

Another wrench you might like is the Giustaforza, a $150 Italian bicycle-specific model that I reviewed a while bike and now keep in my toolbox because it's so handy. Here's a link where you can order it. Another one that's very low tech but does work for most stem/bars with basic 4mm bolts is Ritchey's Torque Key. It's preset and only does 5 Newton meters but that's right for most bolts and most Ritchey stuff. It only has the 4mm Allen bit, though, so it's not that versatile, but if you have only, or mostly 4mm Allen bolts it could work. It's $20 and is a click-type tool small enough to take anywhere.

If you're interested in reading many more tips about caring for carbon bicycles and components, visit this link,

To proper torquing,Jim

----------------------------------------------

Q: Hi Jim,

I need to change the tyre of my bike and I'd like to order it online. I'll be able to fit it myself but I'm not sure which size is the right one. If I read the number on the old front tyre it says 700 x 38c. This is a normal tyre, while at the back I have an anti-puncture Schwalbe tyre, and the size on it is 700 x 32c. So now I'm confused. Which size should I get: 700 x 38c or 700 x 32c? And, where can I buy it online?

Hope you can help,Antonell

A: Hi Antonell,Your tire sizes of 700 x 38c and 700 x 32c mean that they are both the same diameter (700c) but that one is 38mm wide and the other is 32mm wide. In other words, you have one tire wider than the other tire.

It's actually up to you how wide you want your tires to be. You can choose whatever width you want as long as it's a 700c tire and as long as it's not so wide that it rubs against your frame. Common 700c tire widths (different brands and models of tires come in different widths) include 23mm, 25mm, 28mm, 32mm, and sometimes 38mm and wider.

Typically, you would use a wider tire to get a softer, more comfortable ride and some additional flat tire protection, and you would use a narrower tire to get more performance and to save some weight. It's really just up to how you want your bicycle to ride. If you ride off road the wider tires are good for more traction, too.

Now, for a good source for bike tires you can try BikeTiresDirect. They often have good specials.

Thursday, February 5, 2009

Q: Hope you can help, Jim. The local bike shop cannot remove the Campagnolo carbon seatpost from my Litespeed. They have lubed it and heated the seat tube of the frame and still can't budge it. Any suggestions?

Thanks,Ed

A: It'll sound a little strange, Ed, but you can try removing the crankset and bottom bracket from the frame. Then tip the bike upside down and pour some Coke (yes, the drink), down the seat tube of the frame with a funnel to get plenty in there. Now leave your bike upside down with the Coke in there and wait a few days and if you're really lucky, the Coke will penetrate and break the corrosion that has bonded the seatpost to your frame. You can tap on the frame and the seatpost with a rubber mallet (don't damage anything) to vibrate the parts and get the Coke to work its way in between. You can also try ammonia but Coke is safer to handle.

If that doesn't work, you could try freezing the seat tube of the frame with some dry ice, which might do it, too. And, I'm sure you already know that you can cut the post out, too, though that's a pain that takes a bit of work and time. You would cut off the top of the post and then either machine the seatpost out with a bit the same diameter as the post, or you would cut the post with a hacksaw that fits inside the post by making vertical cuts around it until you can break out slices of the post and eventually get the whole thing out. A lot of work, but doable. Wear a good face mask, though. You don't want to breathe carbon dust.

I'll keep my fingers crossed that the Coke trick works for you,Jim-----------------------------------------------

Q: Jim - When shifting from the big ring to the small ring on my triathlon bike (Felt B2) the chain will sometimes drop off the big chainring but not engage the small chainring. It will stay up against the side of the big ring and I can spin the cranks freely like I've shifted into neutral! The motor (me) is disengaged from the transmission and there is no power to the rear wheel. It's very frustrating and when it happens I've got to shift back to the big ring and try again (as I start uphill, or fall off my rollers!).

The front derailleur is a Shimano Dura-Ace, the chain is a Shimano Ultegra 10 speed and the crankset and rings are FSA SLK 53/39. The shifting is friction, not indexed. If an agressive shift is used to throw the chain over farther, faster, the chain may drop (off the inside ring). I've always heard that double front chainrings are simpler and more trouble free than triple, but I never had problems with my road bike (triple) like I've had with this. I've been told to ease up on the pedals to reduce chain tension, (but that's not always gonna happen) Can this be fixed?

Thanks in advance,Aaron

A: Thanks for writing, Aaron. It's essential to ease up on front shifts so that would be the first thing to try. You should always take all pressure off the pedals when shifting the front derailleur. Any other shifting technique is asking for trouble. The jumps between rings are just too big and the power you can put on the chain and rings is just too extreme. Keep in mind that when you push on the pedals the chain becomes a solid steel bar and it does NOT want to move sideways. It's only when you take all the pressure off that the chain gets flexible and has the sideways lateral play to shift smoothly from ring to ring. Experienced racers know this and even in the heat of a race, if they're smart, they will baby the front shifts to ensure no problems. Doing anything else is risking losing the race.

Having said all that, front derailleurs are among the most difficult parts to adjust on a bicycle and even pro mechanics have trouble with it. You might find that if you bring your bike to an expert mechanic they can solve the problem by fine-tuning the front derailleur (a common mistake is incorrect positioning on the frame - see diagram). Be sure to explain to them the problems you're having and also insist that they take a real test ride to experience the shifting on the road, not just on the repair stand. If they balk at this request, or seem disinterested, find a shop that really wants to figure out the problem and help you out. And, even if they're super nice and helpful, if they can't fix the problem, you should consider trying another mechanic to see if he/she has more experience with front derailleurs. (They seem simple, but they're anything but.)

One more thing to check is your cable. If it's sticky (like would happen if energy drink dripped on the frame and got on the cable or the cable guides), that will make the derailleur shift slowly or even not at all. Cleaning and lubing the cable is easy and might also solve the problem if you have a sticky cable. It could be worn or rusty, too. If so, replace it.

The whole thing could very well be your shifting technique, though, so you should try shifting with finesse and seeing if that solves the problem right away. It might. Good luck!

Jim---------------------------------------------------

Q: Howdy Jim,The foam pads on my Giro Transit II (mfg. date March 04) helmet have become so stinky that when sweat drips down over them onto my face, I can hardly stand it. I live in Santa Cruz, CA, not too far from Bell Sports, the company that makes Giro helmets, so I called them about replacement pads and they told me they are unavailable. Furthermore, they told me that the helmet should be replaced every 3 years anyway, because the material breaks down and is no longer safe. This is nuts! Is it not possible to design a good helmet that will last longer than 3 years? I'm sure thousands of years from now, Giro/Bell will be well-represented and studied by archaeologists digging through the mountainous middens of debris created by our throwaway culture. Any thoughts on the short life-cycle of the bicycle helmet?

Cheers,David

A: Thanks for the great questions, David. Here's what I'd do: take your helmet on down to the great folks at the Spokesman in Santa Cruz and ask if by chance they can break out their replacement pads box and see if they have any old pads you can put in your helmet. That's what I did not too long ago on my 4-year-old Giro and they had just what I needed - the exactly right pads. I think the pads cost me about $5, a lot less than a helmet.

And, yes, the helmet companies say you have to replace the helmets for max safety, but most riders don't... especially with the escalating cost of the fancier helmets. Maybe in the worst accident you'd be at more risk, but I haven't seen any scientific proof of this. It sounds logical because the impact material in the helmets is polystyrene foam that protects less over time supposedly, but I don't really know if it's true. If you'd like to learn a lot more about helmets and possibly the facts on how long they will protect you you might visit the Bicycle Helmet Safety Institute a good online resource.

I think the Spokesman will be able to help you out.Jim-------------------------------------------